1. Field of the Invention
The present invention relates to electrical connectors for circuit boards.
2. Description of the Related Art
An electrical connector with a receiving groove having contact elements so that when it receives a circuit board with contact pad on its leading edge, the contact elements are brought into contact with the contact pads is well known. Such an electrical connector generally has a pair of guide sections for guiding the circuit board to prevent the circuit board from tilting.
Japanese patent application Kokai No. 288153/95 discloses such an electrical connector. This connector includes a connector housing which has a front edge holding section with a receiving groove for receiving a leading edge of a circuit board and a pair of guiding sections extending upward from opposite ends of the front edge holding section for guiding the circuit board. A plurality of contact elements are disposed in the front edge holding section so that when the circuit board is inserted, they are brought into contact with the contact pads of the circuit board. The guiding sections have grooves having a width slightly greater than the thickness of the circuit board so as to receive the side edges of the circuit board for guiding the circuit board to a predetermined position. A pair of projections are provided on opposed faces of the grooves so as to engage a aperture of the circuit board for lock when the circuit board is inserted to the predetermined position.
However, the circuit board can fall off from the connector when it receives a vibration or impact. In order to solve this problem, it has been proposed that the guiding grooves be narrowed so as to hold the circuit board. However, this makes it difficult to insert the circuit board in the connector.
Accordingly, it is an object of the invention to provide a circuit board electrical connector which is able to hold a circuit board at a predetermined position against vibrations or impacts.
According to the invention there is provided a circuit board electrical connector which includes a connector housing having a front edge holding section with a receiving groove for receiving a leading edge of a circuit board having a plurality of contact pads on the leading edge and an aperture or notch therein, and a pair of guiding sections extending upward from opposite ends of the front edge holding section for guiding the circuit board; a plurality of contact elements provided in the receiving groove for contact with the contact pads of the circuit board; a pair of insertion slots provided in the guiding sections and having a width slightly greater than a thickness of the circuit board; at least one pair of pressure portions provided on opposed faces of one of the insertion slots such that a distance between the pressure portions is slightly less than the thickness of the circuit board so as to hold the circuit board between them; and at least one pair of engaging projections provided on the pressure portions for engagement with the notch or aperture of the circuit board when the circuit board is inserted in the receiving groove.
The circuit board is inserted into the predetermined position while abutting one only the engaging projections of the guiding section and expanding the insertion slots. When the circuit board is inserted in the predetermined position, the engaging projections of the guiding section enter the aperture or notch of the circuit board to prevent coming off of the circuit board. When the engaging projections enter the aperture or notch, the insertion slots return to the original width, permitting the pressure portions to hold the circuit board between them.
If vibrations or impacts are applied to the electrical connector or the circuit board, they are absorbed by the pressure portions, thus preventing coming off of the circuit board. If a pull is applied to the circuit board, in addition to the engagement by the engaging projections, the friction at the pressure portions prevents coming off of the circuit board. The engaging projections abut against the lower edge of the aperture or notch of the circuit board to prevent the coming off of the circuit board.